A combined alkali extraction--ethidium bromide technique for the measurement of DNA in small pieces of tissue

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Accurate DNA extraction is crucial for molecular biology techniques.
• Assessing DNA integrity and nucleotide pool dynamics is vital in cellular research.
• Radioactive labeling provides insights into DNA synthesis and metabolism.

Purpose of the Study:

• To present a method for DNA extraction from small tissue samples using alkaline solutions.
• To demonstrate the simultaneous quantification of DNA and its radioactivity.
• To show the degradation of RNA during the alkaline extraction process.

Main Methods:

• Extraction of DNA from small tissue samples using alkaline solutions (0.1--0.5 N NaOH) at elevated temperatures.
• Determination of DNA concentration via ethidium bromide fluorescence.
• Measurement of radioactivity in both DNA and the nucleotide pool using aliquots from the extracting solution.

Main Results:

• Alkaline solutions effectively extract DNA from small tissue samples.
• RNA is completely destroyed under the applied alkaline conditions.
• The method allows for direct determination of DNA concentration and radioactivity in DNA and nucleotide pools.

Conclusions:

• Alkaline extraction is a simple and effective method for DNA isolation from small tissue samples.
• This technique is suitable for studies involving radioactive labeling, enabling simultaneous DNA and radioactivity assessment.
• The method's ability to degrade RNA simplifies downstream analyses by eliminating this contaminant.